CN1278835C

CN1278835C - Cutting piece

Info

Publication number: CN1278835C
Application number: CNB2004100343120A
Authority: CN
Inventors: 宾德尔·马可; 龙佩·马库斯; 尤恩·弗朗茨·施托克鲍尔
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2003-04-10
Filing date: 2004-04-09
Publication date: 2006-10-11
Anticipated expiration: 2024-04-09
Also published as: EP1466686A3; US20050025595A1; AU2004201314A1; US7066694B2; GB2400337A; CN1550302A; GB0308287D0; EP1466686A2

Abstract

A cutting plate comprising: a working end for engaging a workpiece, an axis of rotation, a pair of oppositely arranged first faces inclined axially rearward from the working end in an axial plane intersecting said first faces, a pair of second faces alternately arranged between the first faces, wherein the second faces are inclined axially rearward from the working end in an axial plane intersecting said second faces, and a pair of axis parallel front faces. Each of the front faces is bounded on three sides thereof by a respective first face and the pair of second faces. Each second face is inclined radially inward from a transitional edge with a respective rotationally leading first face in a plane normal to the axis intersecting said transitional edge with a respective rotationally leading first face. Each first face is inclined radially inward from a transitional edge with a respective rotationally leading second face in a plane normal to the axis intersecting said transitional edge with a respective rotationally leading second face, as the cutting plate rotates.

Description

Cutting member

Technical field

The present invention relates to cutting member, relate in particular to and be applicable to the cutting plate that is used with drill bit.More particularly, the present invention relates to (but being not limited to certainly) drill bit cutting plate as rotary cutting tile.The invention still further relates to a kind of drill bit and electric drill that has a kind of like this cutting plate.

Background technology

The not only hard but also smooth host material of the smooth protective layer of ceramic tile and ceramic tile itself makes revolving ceramic tile cutting have all difficulties.Known ceramic tile cutting method comprises that the drill bit that at first uses a minor diameter cuts an aperture and make the possibility of ceramic tile protective layer and matrix cracking drop to minimum on protective layer.When ceramic tile by break-through behind aperture, re-use the drill bit that diameter enlarges successively and come the hole is diffused into the size of requirement, thereby reduce the risk that ceramic tile damages.But this known method has following defective: require the hole of diameter to need a plurality of drill bits that the different fixing diameter is arranged in order to bore one on ceramic tile.

A kind of drill bit of seeking to overcome the problems referred to above is disclosed among the open text WO 03/061927A1 of international patent application.This drill bit has a cutting plate, and cutting plate is positioned at an end of the cylindrical handle that has rotating shaft.From its side view, this cutting plate has the main part of a rectangle, and this rectangular body partly is seated at this handle and one from the gable that this main body is extended (being that gable extends from main part).This gable ends at one and has the bocca part of little chisel edge foremost at it.This chisel edge is limited by the front of pair of angled and the flank of pair of angled.This has formed chisel edge to the intersection between the inclination flank, and should the inclination front just defines the length of chisel edge.The flank of each inclination axially recedes away from chisel edge, up to joining with corresponding inclined side.The front of each inclination also axially recedes from the respective end of chisel edge, up to joining with the corresponding axis that is parallel to the front.In the once-through operation in use, the hole in the ceramic tile stably is increased to the complete working diameter of drill bit from very little diameter.

Cutting edge at the beginning of one is formed on inclination flank and a corresponding intersection that rotates between the guiding inclination front, and inferior a side cut is formed on inclined side and the corresponding intersection that rotates between the guiding front.Inclination flank and inclination front also radially slope inwardly from their first cutting edge of corresponding rotation guiding and time side cut.But the inclination front is trailed main the side cut from their corresponding rotations and is radially sloped inwardly, but this parallel front is not a radial skew in any case.For clarity sake, face of ' radially slope inwardly ' or limit are meant from described along leaving towards rotating shaft trend or the direction that tilts from a set point.

Therefore, pass with the plane of rotating shaft direct cross and comprise that the cross section of just cutting edge illustrates inclination flank and one first parallelogram of front restriction.In this first parallelogram, first cutting edge is arranged in the corner that separates farthest, and the inclination flank provides the relief angle of first cutting edge.

Similarly, pass with the arbitrary plane of rotating shaft direct cross and comprise one second parallelogram that the cross section of time cutting edge illustrates inclined side and limits previously.In this second parallelogram, inferior cutting edge is arranged in the corner that separates farthest, and inclined side provides the relief angle of inferior cutting edge.

In two parallelogram, facing surfaces is parallel.In second parallelogram, the angle of inferior cutting edge is 90 ° and deducts the radially intilted angle of inclined side.This is because parallel front is not a radial skew.In second parallelogram, the flank of each inclination and front begin radially to slope inwardly from the corresponding cutting edge just that intersects at that respectively.Therefore, the angle of first cutting edge is 90 ° of summations that deduct inclination flank and the inside radial skew angle of inclined side.Therefore, first parallelogram is more flat and have a first cutting edge more sharp-pointed than second parallelogram, and second parallelogram is more plentiful and have a more blunt or more not sharp-pointed inferior cutting edge.For clarity sake, one more the parallelogram of " flat " mean to compare and limit a littler zone, or fewer parallelogram of " flat " with the more plentiful parallelogram of an equal side.Certainly, in the parallelogram of given side, rectangle defines maximum Probability Area.

Though the sharp-pointed cutting edge just of the disclosed drill bit of WO 03/061927 A1 can have the advantage of accelerating cutting tile in the early stage, when being used for hard relatively and abrasive materials, in the time of for example on the ceramic tile, these initial advantages are not lasting.Sharp-pointed first cutting edge often is worn and rust very soon.And these sharp-pointed cutting edges are crisp and are easier to fragmentation.The most preceding working end of this drill bit in the chisel edge zone is pretty troublesome, and in this zone, the physical dimension of cutting plate is very little, and sharpening is several times again not have enough rich materials to make cracked cutting edge.This has reduced the life-span of drill bit.And then if the side that tilts is sharply axially sweptback, angle drops between 30 ° to 60 ° the scope, and that one geometry of cutting plate in this zone of chisel edge becomes especially little.In this case, fractureing of cutting edge may cause the most preceding working end of cutting plate to be removed fully, thereby can not make its sharpening again.

Summary of the invention

The present invention attempts to overcome these shortcomings by a kind of cutting plate is provided, or alleviates them at least, and this cutting member comprises:

The working end is used for contact workpiece;

Rotating shaft;

The first surface of a pair of positioned opposite, described a pair of first surface begin axially to recede from the working end by the axial plane that intersects with described a pair of first surface;

A pair of second surface, alternate being arranged between the described a pair of first surface, described a pair of second surface begins from the working end by with this axial plane that described second surface intersects axially being receded; With

The parallel front of a pair of axle, alternate being arranged between the described a pair of second surface, and axially extend back from described first surface, wherein three sides of each front are limited by an its corresponding first surface and described a pair of second surface,

Wherein when cutting member rotates, each second surface begins from a transition limit of the first surface of the relation of being in a leading position when rotated accordingly along sloping inwardly with the axle quadrature and with the planar radial that intersects on the transition limit of first surface, thereby formed relief angle in back, described transition limit and the transition limit has formed cutting edge

It is characterized in that, when cutting member rotates, each first surface begins from a transition limit of the second surface of the relation of being in a leading position when rotated accordingly along sloping inwardly with the axle quadrature and with the planar radial that intersects on the transition limit of second surface, thereby has formed relief angle in back, described transition limit and the transition limit has formed cutting edge.

At a preferred embodiment, the invention provides a cutting plate, cutting plate comprises: a working end is used to engage workpiece; A rotating shaft; The first surface of a pair of positioned opposite in the axial plane that intersects with described first surface, begins axially to recede from the working end; A pair of second surface, alternate being arranged between the first surface, wherein in the axial plane that intersects with described second surface, second surface begins from the working end axially to recede; With the parallel front of a pair of axle.Each front is limited by a corresponding first surface and a pair of second surface in its three side.With the axle quadrature and and the plane of intersecting with the transition limit of corresponding rotation guiding first surface in, each second surface begins radially to slope inwardly from the described transition limit with corresponding rotation guiding first surface.When cutting plate rotates, with the axle quadrature and and the plane of intersecting with the transition limit of corresponding rotation guiding second surface in, each first surface begins radially to slope inwardly from the described transition limit with corresponding rotation guiding second surface.This can be pair of planar or a pair of surface that comprises a plurality of separate planes to second surface.

Therefore, the parallelogram that first and second surfaces limit can be the parallelogram of arbitrary shape, scope from the flat parallelogram of the part that has sharp-pointed cutting edge to the rectangle that comprises four right-angle sides.Parallelogram is more near rectangle, and wherein the area that is comprised is big more, and the most preceding working end of cutting plate is firm more.This makes cutting plate to caused fractureing of cutting edge by fragmentation tolerance be arranged more.Therefore cutting edge can be located to have more invasive mode with respect to workpiece, to improve cutting speed, simultaneously the cracked probability bound of cutting edge built in an acceptable degree.

Preferably, chisel edge by one of paired first or second surface to foremost intersection point is limited in the working end.This chisel edge has on one side, and the skin that is used to invade workpiece begins boring procedure.More crisp at cutting plate chisel edge foremost than a cut point, therefore be not easy to fragmentation.The length of chisel edge by another to first or second surface limit.If chisel edge is cracked, can by grind arbitrarily a pair of first or second surface become sharp-pointed again.

Preferably, form chisel edge should to first or one of second surface to the angle that constituted in 90 ° to 150 ° scope, chisel edge enough sharply comes the skin of cutting tile and is not easy fragmentation like this.Preferably, by form chisel edge should to first or one of second surface be 100 ° to the angle that is constituted.

Preferably, the transition limit between each first surface and corresponding rotation guiding second surface is first cutting edge.And the transition limit between each second surface and corresponding rotation guiding front is a time cutting edge.Just cutting edge and time cutting edge can be continuous, but are not that to satisfy work piece cut necessary.Second and first surface be respectively just that cutting edge and time cutting edge provide relief angle.

In addition, this cutting plate and then comprise the side surface that a pair of axle is parallel, each side surface in its three side by corresponding second surface and the restriction of a pair of front.A side cutting edge is limited at the intersection of each side surface and a corresponding rotation guiding front.In the plane of intersecting at and this quadrature and with described side cutting edge, each side surface begins radially to slope inwardly from corresponding side cutting edge.

Preferably, the angle that is made of in the axial plane vertical with second surface second surface is in 30 ° to 60 ° scope.More preferably, the angle that is made of in the axial plane vertical with second surface second surface is 43 °.When seeing from the side, along with first surface to the minimizing of angle, the arrowhead form of this cutting plate is sharp-pointed gradually.Because top argumentation, the sharp-pointed relatively angle between the second surface helps and cut out brighter and cleaner hole on workpiece.

Preferably, this cutting plate and then comprise cutting plate accurately is connected to device on the bit sub.A kind of like this jockey helps easily and reliably cutting plate is connected on the handle of drill bit, and the rotating shaft of cutting plate and handle is concentric like this.

This cutting plate is adapted at punching on the ceramic material most.This cutting plate is particularly suitable for punching on ceramic tile.

The invention provides a kind of electric drill that has cylinder axis and have this drill bit.

Description of drawings

By providing example and reference accompanying drawing subsequently, will be better understood in the present invention's detailed description from behind.Wherein:

Fig. 1 is the oblique view that drill bit of the present invention is loaded onto cutting plate;

Fig. 2 is the oblique view of cutting plate of the present invention;

Fig. 3 is the front view of cutting plate among Fig. 2;

Fig. 4 is the vertical view of cutting plate among Fig. 2;

Fig. 5 is the side view of cutting plate among Fig. 2;

Fig. 6 is the cross-sectional view of the A-A line in Fig. 3;

Fig. 7 is the cross-sectional view of the B-B line in Fig. 4;

Fig. 8 is the cross-sectional view of the C-C line in Fig. 3;

Fig. 9 is the cross-sectional view of the E-E line in Fig. 3;

Figure 10 is the cross-sectional view of the F-F line in Fig. 3.

The specific embodiment

Fig. 1 to 3 has shown a kind of drill bit 2 that especially is suitable for ceramic material is done rotary cutting.Drill bit 2 comprises that 4 and one of cutting members (or cutting plate) are the elongate cylinder handle 6 of rotary middle spindle with the longitudinal axis 8.One end of handle 6 is generally the chuck that is applicable to rotating electric drill (not shown) and engages.The other end of handle 6 is provided with a hollow groove 12, and cutting plate 4 then is placed in the groove.The two sides of groove 12 are made up of a pair of relative clamp 14.In use, cutting plate 4 is removably clamped by clamp 14, so that cutting plate is fixed on the handle 6.Cutting plate 4 is formed by the material that is fit to hardness, for example can adopt hardened steel or tungsten carbide and so on material.As shown in Figure 4, (when promptly cutting) in use, drill bit 2 is along the direction rotation of circular arrow R.

When front view was as shown in Figure 3 observed, the shape of cutting plate 4 was roughly a flat arrow.One end of cutting plate 4 has a planar base 16.When cutting plate 4 was surely placed in the groove 12, the bottom 16 just recess 18 with groove 12 was relative.The other end of cutting plate 4 is a pointed tip 20 that is applicable to cut workpiece.Most advanced and sophisticated 20 form one is positioned at drill bit 2 straight chisel edge 22 foremost.The plane of flat bottoms 16 is all vertical mutually with axle 8 with chisel edge 22, and the axis 8 of cutting plate 4 is roughly concentric with the axis 8 of handle 6.

When vertical view was as shown in Figure 4 observed, the shape of cutting plate 4 was as general as a parallelogram.This parallelogram have the parallel relative front 24 of a pair of and axis 8 with another to also parallel narrow relatively side 26 with axis 8.A pair of narrow side 26 respectively is arranged between a pair of front 24, and the parallelogram of this embodiment is a non-rectangle.

Referring to Fig. 3 and 5, each narrow side 26 extends corresponding front shoulder limit 28 towards the tip 20 of cutting member 4 by bottom 16.Form a transition side shoulder limit 28 between each side 26 and its corresponding narrow inclined side 30.Similar to the relation of side 26 and front 24, pair of angled side 30 also respectively is arranged between a pair of front 24.Inclined side 30 is roughly towards some convergences.Each inclined side 30 is extended by corresponding side shoulder limit 28 towards most advanced and sophisticated 20, their wherein ends in the two ends of chisel edge 22 respectively at most advanced and sophisticated 20 places.The length of chisel edge 22 is limited by this terminal point to opposing inclined side 30.When measuring perpendicular to the axial plane of described inclined side 30, the pair of angled side 30 of Hui Juing is comprising a α angle mutually.The α angle of cutting plate 4 can process in 30 ° to 60 ° scope.Wherein, α angle shown in Figure 3 is 43 °.The α angle is more little, and the axial rear side of inclined side 30 tilts steep more.Therefore, the α angle is more little, and the amplification degree of bore dia will be mild more when cut workpiece.Boring will more be cleaned, and the smear metal around the boring will seldom have or even not have.

Referring to Fig. 3,4 and 7, each front 24 from adjacent bottom 16 to the most advanced and sophisticated 20 continuous corresponding straight crop limits 32 that gradually extend to.Form the crop limit 32 of a transition between the front of corresponding inclination with it, a front 24 34.And pair of angled front 34 is assembled mutually.Towards most advanced and sophisticated 20 extensions, they form chisel edge 22 with regard to intersecting at most advanced and sophisticated 20 places from its corresponding crop limit 32 in each inclination front 34.Comprising an angle β between the pair of angled front 34 of this convergence.As shown in Figure 7, this angle β is with respect to measuring perpendicular to the axial plane of chisel edge 22.This respectively is arranged between the inclined side 30 inclination front 34.β angle between the inclination front 34 of cutting plate 4 can be formed in 90 ° within the scope of 150 ° of degree.Wherein, the chisel edge 22 of β angle in 100 ° to 110 ° degree scopes reached optimum balance between cutting intensity and cutting speed.More specifically, the β angle among Fig. 7 is 100 °.

As Fig. 3, Fig. 4 and shown in Figure 5, cutting edge 36 at the beginning of each inclination front 34 forms with its inclined side 30 intersections that are in guiding relation accordingly and when rotated.Each inclination front 34 begins radially to slope inwardly from first cutting edge 36 that its corresponding rotation leads respectively along one and axle 8 quadratures and with plane that described cutting edge just 36 intersects.This inclination front 34 is just forming relief angle (or relief) after the cutting edge 36.The inside radial skew angle of each inclination front 34 is θ, and this oblique angle θ gets the angle amount of the axial plane 37 of the 24 pairs of branches in front with the angle of inclination front 34.The scope at this cutting plate θ angle can be between 1 ° to 20 °.θ angle in Fig. 8 is 9 °.Just the working diameter D36 of cutting edge 36 makes stability increase when cutting plate 4 thrusts workpiece W.

Each inclined side 30 and its corresponding rotation lead 24 intersections, front to form cutting edge 38 one time.Each inclined side 30 is from its corresponding and be in the inferior cutting edge 38 that leads relation when rotated and begin to slope inwardly along one and axle 8 quadratures and with planar radial that described cutting edge 38 intersects.This inclined side 30 produces relief angle (or relief) after inferior cutting edge 38.The inside radial skew angle λ of each inclined side 30, the λ angle is that the angle amount of axial plane 37 plane orthogonal 39 of the 24 pairs of branches in front with inclination front 30 got.The λ angle of this cutting plate 4 can be formed in 3 ° to 15 ° the scope.The included angle X that Fig. 8 and Fig. 9 show is 5 °.The working diameter D38 of inferior cutting edge 38 makes stable increasing property add when cutting plate 4 thrusts workpiece W.

Referring to Figure 10, each side 26 and its are in 24 intersections, front that lead relation accordingly and when rotated and form a side cutting edge 40.Each side 26 begins radially to slope inwardly with axle 8 quadratures and with described side cutting edge 40 crossing planes along one from the side cutting edge 40 that it is in guiding relation accordingly when rotated.This side 26 produces relief angle or relief in side cutting edge 40 backs.The inside radial skew angle γ of each side 26 be from axial plane 37 plane orthogonal 39 of the 24 pairs of branches in front and 26 areas of a room, side angle.The scope at the γ angle of this cutting plate can be between 3 ° to 15 °.The γ angle is 5 ° among Figure 10.Side cutting edge 40 defines the maximum functional diameter D40 of cutting member 4.

The width of chisel edge 22 preferably approximately be cutting member 4 working diameter D40 5% to 20%.Chisel edge 22 is continuous with the first cutting edge 36 that is positioned at its either side.And the cutting edge 40 of each time cutting edge 38 and its respective side is continuous.But, have an interruption between cutting edge 36 and the inferior cutting edge 38 just.Clearly visible as sectional drawing 6, chisel edge 22 is led over the first cutting edge of trailing 36 when rotated.Just cutting edge 36 is then led over corresponding time blade 38 and side cutting edge 40 when rotated.As shown in Figure 4, (promptly 180 °-δ) the anglec of rotation is led over inferior cutting edge 38 and the side cutting edge of trailing 40 to chisel edge 22 when rotated with 180 ° of amplitudes that deduct the δ angle.

Referring to Fig. 3 and Fig. 4, a pair of chamfering or scarf 42 are being extended in bottom 16 between a pair of side 26, and each scarf 42 connects bottom 16 and corresponding front 24 respectively.Scarf 42 is tapered cutting plate 4 fore-ends and narrows, such narrowing in design makes it easier insertion handle 6 in assembling process the groove 12.Cutting plate 4 also has the fossaperturate 44 of a shallow rectangle on each front 24, this fossaperturate 44 extends to the approximate midpoint position of cutting plate 4 from the position that is adjacent to bottom 16.Fossaperturate 44 is symmetrical in axle 8.Each fossaperturate 44 have one with the parallel plane recess face 46 in the plane 37 of the 24 pairs of branches in front.Fossaperturate 44 has an opening 50 at the end facing to bottom 16.Opening 50 makes half of each recess face 46 about intrusion scarf 42.Each recess 44 has a pair of and recess sidewall 48 axially parallel, and this sidewall 48 extends to recess end wall 52 from the openend 50 of recess 44, and this end wall 52 is positioned at the other end of recess 44, and perpendicular to axle 8.When cutting plate 4 was placed in the groove 12 and is clipped on the handle 6, this recess 44 provided a position to admit relative clamp 14 in each side of cutting plate 4.When cutting plate 4 be placed in the groove 12 and guarantee the axis 8 of cutting plate 4 and the axis of handle 68 when concentric, the sidewall 48 of recess 44 and end wall 52 just in time with the clamp alignment of a correspondence.

Referring again to Fig. 1, the length of the recess 44 on the depth ratio cutting plate 4 of groove 12 is dark.A position between the bottom 16 of recess 18 that is arranged in groove 12 and cutting member 4 (when cutting member is clipped on the handle) has a horizontal cylindrical hole 54 that passes clamp 14 and axis 8.Hole 54 in clamp 14 does not have screw thread, and a cylindrical recess 56 facing to handle 6 outsides is arranged.The size of the recess 56 in this hole can be held stove bolt 60 heads 58.The hole 54 of another clamp 14 is threaded so that and bolt 60 threaded handle engagements.In the present embodiment, bolt 60 is cylinder head bolts that have hexagonal recesses 62, and when the head 58 of this bolt was held by recess 56, recess 62 held the hex wrench (not shown) and comes rotating bolt 60.Bolt 60 can be the standard hex hook bolt, but the recess in hole 56 needs to strengthen, and box spanner and hexagon-head are cooperated easily.

Rotating bolt 60 is tightened cutting plate 4, thereby pulling clamp 14 is close together them, and cutting plate 4 just is clamped at therebetween like this.On the contrary, rotating bolt 60 loosens cutting plate 4, thereby makes pincers 14 folders separately, and cutting plate 4 can discharge from groove 12 so that replace or keep in repair like this.

Promptly method as an alternative, cutting plate 4 can brazings, or are glued in the groove 12 the therefore configuration of saving transverse holes 54 and bolt 60 with strong adhesive.Cutting plate 4 even can be integrally formed with axle 6.

In use, drill bit 2 is along the direction rotation of circle arrow R.Chisel edge 22 is by engaging workpiece W etc., and for example ceramic tile begins cutting operation.Chisel edge 22 is shorter relatively, forms one and thrusts the hard outer field point of ceramic tile at first.In case chisel edge 22 has thrust workpiece W, along with first cutoff edge 36, then be time cutting edge 38 cut workpiece W, the hole that is formed on wherein little by little enlarges.Final cutting operation is carried out by side cutting edge 40, and this cutting edge helps to cut out a bright and clean hole on workpiece W.This side cutting edge 40 is gone back pilot bit 2 with straightaway, and promotes fragment to remove from the point of cutting plate 4.

Shown in Fig. 8,9 and 10, cutting plate 4 along with axle 8 plane orthogonal in the cross section that intercepts be parallelogram, and comprise just cutting edge 36, inferior cutting edge 38 and side cutting edge 40 respectively.These

cutting edges

36,38 and 40 always are positioned at the relative angle place that separates farthest.Angle λ is fixed by the gradient of inclined side 30, thereby angle θ controls the shape of the parallelogram that is limited by inclined side 30 and front 34.If angle θ equals angle λ, so the parallelogram that is limited by inclined side 30 and front 34 is a rectangle, all angles become the right angle.If angle θ is greater than angle λ, so just cutting edge 36 jumps to about 1/4th commentaries on classics that take the lead time cutting edge 38 and side cutting edge 40.This can illustrate by the position of the first cutting edge 36 shown in the comparison diagram 8 and the position of inferior cutting edge shown in Fig. 9 and Figure 10 and side cutting edge 38,40.Therefore, there is little discontinuity between each first cutting edge 36 and the corresponding time cutting edge 38.

If cutting plate 4 is made by tungsten carbide type KCR05, the then preferred angle μ of cutting edge 36 just is 86 °.Just the angle μ of cutting edge 36 is 86 °, reaches balance preferably at sharp-pointed and cutting tile between the excessively not frangible hardness.

In this manual, cutting plate and cutting member can be used alternatingly in due course.

Claims

1. cutting member (4) comprising:

Working end (20) is used for contact workpiece;

Rotating shaft (8);

(20) are begun axially to recede by the axial plane that intersects with described a pair of first surface (34) from the working end for the first surface of a pair of positioned opposite (34), described a pair of first surface (34);

A pair of second surface (30), alternate being arranged between the described a pair of first surface (34), (20) begin by with this axial plane (37) that described second surface (30) intersects axially being receded described a pair of second surface (30) from the working end; With

The parallel front (24) of a pair of axle, alternate being arranged between the described a pair of second surface (30), and axially extend back from described first surface (34), wherein three sides of each front (24) are limited by an its corresponding first surface (34) and described a pair of second surface (30)

Wherein when cutting member (4) rotates, each second surface (30) from a transition limit (38) beginning of the first surface (34) of the relation of being in a leading position when rotated accordingly along sloping inwardly with axle (8) quadrature and with the planar radial that intersects on the transition limit (38) of first surface (34), thereby formed relief angle in back, described transition limit (38) and transition limit (38) have formed cutting edge

It is characterized in that, when cutting member (4) rotates, each first surface (34) from a transition limit (36) beginning of the second surface (30) of the relation of being in a leading position when rotated accordingly along sloping inwardly with axle (8) quadrature and with the planar radial that intersects on the transition limit (36) of second surface (30), thereby formed relief angle in back, described transition limit (36) and transition limit (36) have formed cutting edge.

2. a cutting member according to claim 1 (4), wherein paired first or second surface (34; 30) (20) intersection foremost defines chisel edge (22) in the working end for a pair of in.

3. a cutting member according to claim 2 (4) wherein forms the paired first surface (34) of chisel edge (22) or angle (β) that second surface (30) is constituted in 90 ° to 150 ° scopes.

4. a cutting member according to claim 3 (4), wherein forming the paired first surface (34) of chisel edge (22) or angle (β) that second surface (30) is constituted is 100 °.

5. one kind according to the described cutting member of one of claim 2 to 4 (4), wherein the length of chisel edge (22) by another to first or second surface (34; 30) limit.

6. one kind according to the described cutting member of one of claim 2 to 4 (4), the transition limit that wherein is positioned between each first surface (34) and the corresponding rotation guiding second surface (30) is first cutting edge (36), and the transition limit that wherein is positioned between each second surface (30) and the corresponding rotation guiding front (24) is second cutting edge (38).

7. one kind according to the described cutting member of one of claim 2 to 4 (4), and wherein cutting member (4) and then comprise the parallel side (26) of a pair of axle is limited by a corresponding second surface (30) and a pair of front (24) in its three side.

8. a cutting member according to claim 7 (4), one of them side cutting edge (40) is limited to the intersection of each side (26) and corresponding rotation guiding front (24), wherein and axle (8) quadrature and and described side cutting edge (40) plane of intersecting in, each side (26) are located radially to slope inwardly since a corresponding side cutting edge (40).

9. one kind according to the described cutting member of one of claim 2 to 4 (4), and wherein in the axial plane vertical with second surface (30), the formed angle [alpha] of second surface (30) is in 30 ° to 60 ° scope.

10. one kind according to the described cutting member of one of claim 2 to 4 (4), and in the axial plane vertical with second surface (30), the formed angle [alpha] of second surface (30) is 43 °.

11. one kind according to the described cutting member of one of claim 2 to 4 (4), wherein cutting member (4) and then comprise is used for cutting member (4) accurately is connected to device (44) on the handle (6) of drill bit (2).

12. one kind according to the described cutting member of one of claim 2 to 4 (4), wherein cutting member (4) is to be used for punching at ceramic material.

13. a drill bit (2) has cylinder axis (6) and as the described cutting member of one of claim 2 to 4 (4).

14. an electric drill that has drill bit (2), described drill bit (2) have cylinder axis (6) and as the described cutting member of one of claim 2 to 4 (4).